Abstract:

The environmental impact of flow alterations has emerged as an important aspect of river management.However it is often difficult to find a single indicator linking the flow regime to the sustainability of the riverine ecosystem.So,this paper proposes an integrated method for the instream flow assessment,which includes basic flow requirement,evaporation requirement and seepage requirement.There are three innovative features in this study.(a) The propose of ecological partition solves the previous problem without different ecological requirement in the riverine.(b) Comparing with the traditional approach,this model involves the influence of the human being by including the emissions of sewage,population density to the river.(c) Aiming at more accurate assessment,the method extends to a larger spatial scale,being helpful for river managers in decision making.As the society development affecting more and more the instream flow,people have to solve the connection between environment and river management.So this paper synthesize ecological demand and activities of human being,with the normal production ecological environment water demand estimation model.The model is based on river flow,rainfall and other hydrological data,combined with the soil conditions of the district environmental water demand estimates.
To appropriately take environmental flow requirements into consideration in water resources planning and management,it is required that models used in water resources planning can accommodate the specific characteristics of the environmental flow requirements.Actually activities of human being is the most important factor in the river management,so the indicator includes ecological demand and activities.Then according to the ecological and social life demand,different algorithm can be used in different partition.
After introducing the main algorithm,this new algorithm is applied to the Pu River.The results showed that,ecological water requirement amount in the Pu river is 4662584 m3,and the results changed significantly from season to season,being affected by human activities (the emissions of sewage,population density etc.).The results allow for assessment,which includes the high flow pulses and small and large floods that are part of an environmental flow requirement,providing a basis for the study of seasonal rivers.